John “Junior” Gotti got a boost from a federal judge who questioned the feds’ decision to put the former mob leader on trial a third time after two juries failed to return a verdict.

“Does the government get to have endless trials until they get it right? The fourth, fifth or sixth?” Manhattan federal Judge Shira Scheindlin asked yesterday at his arraignment on new charges.

“It’s a problem. We didn’t get it right once. We didn’t get it right twice. I’m very troubled. You get to try again? That’s a very weird idea,” Scheindlin said.

The judge aired her concerns after prosecutors argued that a newly rewritten indictment paves the way for them to use evidence of four uncharged murders to prove Gotti’s involvement in the Gambino crime family.

Scheindlin granted a request by Gotti’s lawyers to postpone the trial date from July 5 to Aug. 28 to give the defense team time to prepare for the feds’ beefed-up case.

Gotti pleaded not guilty to the new indictment, which adds money laundering and witness-tampering charges to those he already faced – most notably the 1992 kidnapping of radio host Curtis Sliwa.

The normally clean-shaven son of John “Dapper Don” Gotti came to court sporting a scruffy beard – something he never could have done while running the Gambino crime family, according to mob rules that prohibit facial hair.

“My daughter wanted to see me with a new beard, so I says, ‘Why not?’ ” Gotti said outside of court.

Defense lawyer Charles Carnesi said starting the trial any sooner would be a problem since Gotti’s wife Kim is due to give birth in early August and has had a difficult pregnancy.

The feds launched their latest grand jury probe after Gotti refused to take a plea offer that would have landed him behind bars for less than four years and forced him to pay $500,000 – a fraction of the 30-year sentence and $25 million forfeiture he faces if convicted.

Prosecutors said the evidence to prove Gotti tried to stop mob turncoat Michael “Mikey Scars” DiLeonardo from cooperating in 2003 would feature several new witnesses – including one he re fused to identify.

Assistant U.S. Attorney Victor Hou revealed that mob canary Joseph D’Angelo filled the feds in on a second, uncharged incident of witness tampering from 2005. That case relates to the prosecut ion of acting Bonanno boss Vincent “Vinny Gorgeous” Basciano.

Scheindlin said she would stick to an earlier ruling that stops prosecutors from getting into Gotti’s alleged links to murder unless the feds come up with new evidence.

“Find something new or don’t go there,” the judge said. “You had this information from the beginning. There’s no new evidence. I’m troubled that after years you would redraft the indictment to get around a ruling. It’s a work-around.”